This invention relates to a method of generating a non-reproducible printed image which can be utilised in the production of documents which are not to be copied.
Valuable documents such as cheques, vouchers, identification documents and the like are subject to fraudulent copying, and various schemes have been adopted in order to make such copying difficult. However, as the technology available to counterfeiters becomes more sophisticated, it is necessary to adopt more and more sophisticated measures to prevent unauthorised copying of such documents.